The following terms are briefly defined here for use in the following description:
A telecommunication platform (also called a TC platform) is a switching center or telecommunications installation, for example (also called a PBX or “Private Branch Exchange”). Such TC platforms offer mostly SIP-based VoIP/Video-over-IP technologies. A telephone terminal is, for example, a telephone, smartphone, computer used to establish or operate a telephone connection (“call”) or a data connection, or another—possibly virtual—type of terminal.
A cloud communication server (CCS) is, for example, a SaaS Cloud platform for collaborative cross-team work. It allows teams to receive what they need for effective communication in a single client (also called a CCS client).
A CCS client is, for example, an application software (app) that combines voice, video, screen sharing, messaging, chat, file sharing, etc., making collaborative work easy and trouble-free. Such a CCS client on a cloud communication server is based primarily on WebRTC technology and can be installed on a (telephone) terminal, for example.
The following abbreviations are explained below:                API: Application Programming Interface        App: Application, Application software or environment, Software, Web application        ATC: Advanced Telephony Connector        CSTA: Computer Supported Telecommunications Applications (ECMA)        CTI: Computer Telephony Integration (e.g., CSTA, TAPI)        ECMA: Ecma International Standardization Board        ONS: One-Number Service (in an internal/external company network)        PBX: Telecommunication installation, Telecommunication platform, Switch        PD: Preferred (communication terminal) Device        SIP: Session Initiation Protocol        TAPI: Telephony Applications Interface (Microsoft)        UC: Unified Communication        WebRTC: Web Real-Time Communication        
With One-Number Service, a user can be located anywhere. The user can always be reached at the one telephone number that the user has given to other people. With One-Number Service (ONS) a UC application forwards all of the user's calls to his preferred device. The user decides which terminal (telephone) he wants to use for his communication (such as an office phone, mobile phone, phone in the internal/external company network, private phone, conference room, phone in a public place, CCS client).
Unified Communication (UC) involves the integration of communication media such as voice, video, screen sharing, messaging, chat, and file sharing in a uniform application environment, making collaborative work easy and trouble-free.
Unified Communications (UC) solutions are distinguished in that a UC user (hereinafter also designated as a user) can be reached via various communication media (generally called devices in this field). Depending on the situation, he may want to establish whether and via which media or devices he wishes to be reached. A significant class of devices comprises telephones (land-line and mobile). A UC user generally has several such devices. From the point of view of the communication system, some of these devices are switched in externally through gateways and can be included in the communication system as virtual devices.
The UC feature “One-Number Service” (also abbreviated as ONS) is especially significant because it hides the UC user's exact location and the actual device he is using from his communication partners. The issue therefore arises of how the following can be achieved:                assigning UC users to the devices assigned to them,        dynamically changing the assignment of devices (for external devices in particular),        activating/deactivating the active device(s), and        simultaneously hiding the complexity of these assignments from the applications,        in order to keep the overall implementation expenditure low.        
In the context of the present invention, the following practical examples (also called Use Cases) are cited:
The following devices, for which One-Number Service is to be provided, are assigned to a UC user:                system telephone, connected directly to the communication system        mobile telephone, externally switched through a gateway to the communication system,        home office telephone, externally switched through a gateway to the communication system.        CCS client, a client assigned via a cloud communication serverDepending upon the location or situation, the UC user may wish to be called:        If he is in the office: on the system phone and the mobile phone (because he is not always at his desk), but not on the home office phone.        If he is in the home office: Only on the home office phone.        If he is traveling: Only on the mobile phone (office hours), otherwise redirected to voice mail. In certain situations, however, the mobile number should not be called as an external device, but instead an alternative external phone number (e.g., a hotel).        
The prior art offers solutions to this, but they do not meet all of the requirements listed above and are very complex to execute:
Utility model DE 20 2011 003 225 U1 and patent application WO 2014/060008 A1 describe the possibility of managing a virtual terminal for a participant or a group of participants. In this case, for example, the user of a telephone system has a mobile phone (with GSM and WLAN connections, if applicable). This mobile phone is currently not included in the system-specific communication scenarios. The user, for example, cannot forward conversations on the mobile phone to other participants in the communication system or accept conversations from another participant in the communication system. For this case, DE 20 2011 003 225 U1 and WO 2014/060008 A1 offer a remedy fully integrated into the communication system, for which no additional hardware is needed. Calls to and from the mobile phone are fully associated through an internal (virtual) participant in the communication system.
The procedure implemented by Unify to provide the One-Number Service using a UC application is based primarily on a definition described in ECMA-269, in which the user's device consists of a logical and a physical component. The logical component is the One-Number Service number and the physical component is the preferred device. In most cases, the One-Number Service number is the same as the user's desk phone. The user uses the preferred device to make calls under his One-Number Service number such that the connection number of the preferred device remains hidden from the conversation partner. Instead, the conversation partner always sees a connection to the One-Number Service number.
However, the One-Number Service according to DE 20 2011 003 225 U1 and WO 2014/060008 A1 is complex and expensive to implement. This also involves, in particular, the expense to the client-side application software, because any changes in assignments of active (preferred) devices must be processed actively by each client software. The approach presented here should significantly reduce this complexity. Connection of an external device in the communication system and of One-Number Service should be dynamic, but transparent to the client-side application software. If the assigned phone number is temporarily changed (e.g., hotel scenario), this has no effect on the application software and in particular no effect on the control or monitoring of the corresponding virtual devices.
In addition, the concept according to DE 20 2011 003 225 U1 and WO 2014/060008 A1 has limitations with respect to flexibility: This known version does not allow multiple terminals—as a subset of all devices assigned to the user—to be used simultaneously as preferred devices.
WO 2007/000447 A1 discloses a system for signaling switching statuses between a team module MULAP in a communication unit, to which multiple terminals E1 . . . En for a participant T are assigned, and a ComAss communication module that controls switching of the team module MULAP, wherein the switching statuses of the terminals E1 . . . E3 for the participant T are captured in the team module MULAP. The system is distinguished in that, in the team module MULAP and in the communication module ComAss, a logical terminal LE is assigned to the terminals E1 . . . En of a participant T, in that the switching status v of the participant T is determined from the captured switching statuses of the terminals E1 . . . E3 and entered into the logical terminal LE of the team module MULAP, and in that the switching status v of the participant T entered into the logical terminal LE is signaled to the communication module ComAss.
Under WO 2007/000447 A1, the team configuration of a participant T is developed using that participant's statically configured terminals E1, E2, E3 through two static CTI layers, as shown in FIG. 3.
CTI layer 2 shows the static link between the participant T and the respective linked terminal E1, E2, or E3. This is used today within OSBiz by the following applications:                Middleware components: CSTA Service Provider—CSP        Direct Station Select Server (app for cross-node LED signaling of participant statuses)—DSS        Embedded UC-Server—LAS        
CTI layer 1 projects or condenses, for high-level applications, the status of the used terminal E1, E2 or E3 to the status of the static participant T. This allows the terminal with varying use to be selected from a static configuration. The participant T is therefore, in a mathematical sense, a function of the used terminal E1, E2, or E3.T=f(E1,E2,E3)−finite listThis is used today within OSBiz by the following applications:                UC Server—“UC Suite”        
This process assumes a static assignment of the participant T to his used terminals E1, E2, or E3 (because, for example, the terminal E3 can be used in multiple teams, an E3 change in runtime would require that all affected monitor points be updated in all applications, which is very involved and complex).
With One-Number Service (ONS), a participant T dynamically selects his desk phone E1 or his Circuit Client E2 (CCS client) or any preferred device OND 1, OND 2. In Circuit, this involves the cloud communication server from the company Unify. The participant T uses the dynamically selected terminal to make calls under his One-Number Service number such that the connection number of the respective preferred device remains hidden from the conversation partner. Instead, the conversation partner always sees a connection to the One-Number Service number. This CSTA model according to One-Number Service is shown in FIG. 4. The CTI layer used for this adjusts itself to the respective selected preferred device and dynamically displays the link between the participant T and the respective terminal E1, E2, OND 1, or OND 2. The participant T is therefore, in a mathematical sense, a function of the used preferred device.T=f(Preferred Device)−infinite listThis is used today, for example, by many applications.
This process assumes a dynamic assignment of the participant T to his used terminals or preferred devices E1, E2, OND 1, or OND 2. The applications must follow the dynamic change.